This invention relates to an AC to DC converter circuit having a high power factor in the range of about 90% or greater.
Generally, AC to DC converter circuits include a rectifier which is coupled to an AC potential source and to a load circuit. A capacitor or charge storage means is connected in shunt with the rectifier. When the input voltage exceeds the voltage on the capacitor plus the voltage drop across two diodes, assuming a full-wave rectifier circuit, current flows into and charges the capacitor. This charging of the capacitor continues until the input potential reaches a maximum value and starts to decrease. Thereupon, charging of the capacitor ceases and a discharge through the load is effected. Thus, a DC potential having a ripple is provided. Moreover, increasing the size of the charging capacitor tends to improve or reduce the undesired ripple but it also reduces the current conduction period or angle which is highly undesirable due to a lowered value of power factor as will be further explained hereinafter.